The invention relates to a process for preparing a composite particulate material, especially a composite particulate material for use in treating aqueous solutions and vapor phase systems, wherein the composite particulate material has increased effectiveness and resistance to attrition.
Various materials and processes are well known in the art for treating aqueous solutions and vapor phase systems, particularly for the removal of unwanted heavy metals such as lead and the like. A process for removal of heavy metals from aqueous systems is disclosed in U.S. Pat. No. 5,053,139, and a composite ion-exchange material for use in such processes is disclosed in U.S. Pat. No. 5,277,931.
U.S. Pat. No. 5,277,931 discloses the preparation of a composite ion-exchange material wherein porous particles are first sprayed with an aqueous basic material and subsequently sprayed with a concentrated aqueous acidic solution of a source of suitable metallic ions. This process for preparation is said to provide a composite material without significant deposit within pores of the support material and without encapsulating the particles of porous material. In practice, composite materials formed in accordance with the teachings of the '931 patent have been found to be undesirably susceptible to attrition. Specifically, large amounts of the primary material, which is typically the most expensive component of the final product, are lost during packaging and shipping of the product.
It is apparent that the need remains for a composite particulate material and a process for preparing same wherein the composite particulate material is resistant to attrition.
It is therefore the primary object of the present invention to provide a composite particulate material and a process for preparing same wherein the primary particles are substantially permanently bonded to the support material, thereby significantly reducing or eliminating the effects of attrition.
It is a further object of the present invention to provide a process for preparing a composite particulate material which is useful in treating aqueous solutions for the removal of heavy metals contained therein.
It is a still further object of the present invention to provide a composite particulate material having an excellent selectivity toward removal of undesirable heavy metals contained in aqueous solutions.
Other objects and advantages of the present invention will appear hereinbelow.